Speaker 1: Welcome to brain Stuff, a production of iHeart Radio. Hey
Speaker 1: brain Stuff, Lauren Voke Obam here with another classic episode
Speaker 1: from the podcast archives. This one has to do with
Speaker 1: a bit of animal behavior that's incredibly well observed yet
Speaker 1: not very well understood, bird migration. Hey, I'm Lauren voke Obama.
Speaker 1: This is brain Stuff, and I have a topically relevant
Speaker 1: scenario for your consideration. Let's say you want a change
Speaker 1: of scenery, so you set out with the clothes on
Speaker 1: your back, your innate knowledge of the world, and zip
Speaker 1: all else. Would you be able to travel a few
Speaker 1: thousand miles and wind up somewhere with excellent food options
Speaker 1: and potentially attractive members of your species? And then would
Speaker 1: you be able to get back home a few months later?
Speaker 1: I personally would be hopelessly lost within a week, and yes,
Speaker 1: I would be completely useless during a zombie apocalypse. But
Speaker 1: lots of birds do this every year. Migration can take
Speaker 1: tens of thousands of miles across oceans and continents, and
Speaker 1: often to the exact same summer and winter spots, using
Speaker 1: nearly the exact same roots every time. It's not like
Speaker 1: they have a GPS. Ornithologists have speculated that birds might
Speaker 1: use a number of audio, visual, odorous, and learned social
Speaker 1: cues to get where they're going. But young birds making
Speaker 1: their trip for the very first time have been observed
Speaker 1: to migrate successfully with no chaperones. So, assuming that birds
Speaker 1: aren't feathered cyber drones hacking our global positioning satellites, what
Speaker 1: gives how to birds migrate? Research has revealed that migratory
Speaker 1: birds have vision based magneto reception. They can see magnetic fields,
Speaker 1: and Earth is lousy with magnetic fields. The primary one
Speaker 1: is what makes compasses work. These magnetic fields exist because
Speaker 1: Earth's molten outer core is made up of iron alloys,
Speaker 1: which are switched around by heat coming up off of
Speaker 1: these solid intercore and by the rotation of the Earth.
Speaker 1: That motion and a plus the fact that iron is
Speaker 1: really good at conducting electricity, create a dynamo. A dynamo
Speaker 1: being a generator of electric and magnetic fields, which basically
Speaker 1: makes Earth function like a giant bar magnet. The north
Speaker 1: pole is positive, the south pole is negative, and our
Speaker 1: planet is wrapped in magnetic fields arking between them in
Speaker 1: slopes and curves, and migratory birds can sense those fields.
Speaker 1: Experiments over the past couple of decades have shown that
Speaker 1: birds prepared to migrate south will align themselves with magnetic
Speaker 1: self even in the lab if you create an artificial
Speaker 1: magnetic south. Furthermore, these birds actually see magnetic fields around.
Speaker 1: Researchers fit European robins with either clear or frosted goggles,
Speaker 1: and they found that the birds needed clear vision in
Speaker 1: their right eyes, specifically in order to navigate magnetically. Now
Speaker 1: scientists are studying what biological mechanism might be responsible for this.
Speaker 1: More research needs to be done, but the popular theory
Speaker 1: goes that magnetic fields cause a chemical reaction in birds
Speaker 1: eyes that affect their sensitivity to light, so magnetic fields
Speaker 1: might show up as brighter or darker patterns spread out
Speaker 1: over everything that the bird sees. It's sort of like
Speaker 1: a map on a heads up display. Today's episode is
Speaker 1: based on a video script that I wrote for how
Speaker 1: stuff works dot Com. Brain Stuff is production of I
Speaker 1: Heart Radio in partnership with how stuff works dot Com,
Speaker 1: and it's produced by Tyler Klang and Ramsey Yu. Four
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